Within the SAGITTARIUS trial, we are studying how liquid biopsy—a non-invasive blood test that detects tumor DNA—can guide post-operative therapy in colon cancer patients. Our goal is simple but ambitious: to offer a more personalized treatment to those who need it, and less treatment to those who do not need it.
I have spent many years guiding patients through the difficult path of colon cancer treatment. Surgery remains the standard of care for localized disease—but after surgery, the next step is often uncertain. In fact, imaging techniques do not allow the detection of any residual disease, which can lead to patients developing a tumour again. Therefore, chemotherapy is usually applied to all patients after surgery to prevent this from happening. The SAGITTARIUS trial may demonstrate that some patients can safely avoid chemotherapy and its adverse effects after surgery, either by using personalized therapies based on the molecular characteristics of the tumour or, always with medical supervision, by receiving no treatment at all. This study, with the support of the European Union’s Horizon Europe programme, may therefore lead to a more personalized and cost-effective treatment strategy and, above all, to improvements to patients’ care.
In total, SAGITTARIUS will involve 26 clinical sites across Spain, Italy, and Germany, aiming to recruit 900 patients overall. As of June 2025, more than 100 patients have already joined the study, and 25 clinical centres are activated.
This trial is a true collaborative effort. It brings together surgeons, oncologists, pathologists, nurses, researchers, and data scientists to tackle a complex challenge in real time. Our model is built not only on cutting-edge science, but on trust—trust between patients and their care teams, and between institutions and other stakeholders committed to transforming cancer care.
I am grateful to the patients who have already joined us, and to the clinical teams working tirelessly to bring this vision to life. Together, we are not only testing a hypothesis—we are reshaping the future of colorectal cancer treatment, one patient at a time.
— Clara Montagut,
Head of the Gastrointestinal Cancer Section in the Oncology Department at Hospital del Mar (Barcelona)